Effects of partial constrained viscoelastic layer damping parameters on the initial transient response of impacted cantilever beams: Experimental and numerical results

The effects of partial constrained viscoelastic layer damping on the first milliseconds of the transient vibration of an impacted beam is studied using an analytical model. The viscoelastic properties of the core are frequency dependent and the shear modulus is modelled using a Prony Series. The equations of motion of the system are obtained using Lagrange's equations. The equations of motion are converted in the frequency domain using a Fourier Transform and they are solved for frequency displacements using the assumed modes method. They are then converted back in the time domain using an inverse Fourier Transform. The technique is validated for transient responses using experimental impact force signals. The numerical results are in good agreement with experimental data. Four partial constrained viscoelastic layer damping parameters are studied: the length, the placement, the viscoelastic layer thickness and the constraining layer thickness. It turns out that the length of the partial constrained viscoelastic layer damping has the most important effect on the initial transient displacement while the viscoelastic layer thickness has little effect. Noncausal effects in the model are discussed and are mainly induced when the partial constrained viscoelastic layer damping treatment is poorly effective.